1. Field of the Invention
The present invention relates to a system and method for providing services to mobile stations such as cellular phones, personal digital assistants (PDAs), car navigation systems, etc.
2. Description of the Related Art
Conventionally, there have already been techniques to provide information services to mobile stations, such as cellular phones, PDAs, car navigation systems, etc., and to charge them. Among these, techniques to provide a service restricted to a particular area include the following:
(1) Japanese Unexamined Patent Publication No. 6-189360 [Area-Restricted Mobile Communications System]
With this technique, each portable terminal is preallocated to an area where communication is authorized. For example, when the service area of a cellular phone is described as the Kanto area only, communication is authorized only when that phone is in the Kanto area.
(2) Japanese Unexamined Patent Publication No. 10-327097 [Area-Restricted Mobile Station Information Providing System]
This technique relates to an information providing service system for portable terminals which is restricted to a particular small area. With this system, special devices, called sign posts, for providing services are placed at regular intervals in an area, and services are provided from the devices to portable terminals.
However, the above area-restricted service systems have the following problems:
With the system (1), a service area can be set up for each portable terminal, but it is impossible to set up an authorized area for each individual service. That is, it is impossible to, besides an area where a call can be made, set up an area where a particular information service is available, for example, in such a way that, outside a horse racetrack, a call can be made but access to tip information on horse races is prohibited.
With the system (2), since information is published from the sign posts placed at regular intervals, the service area is physically restricted to an area where a sign post is placed. It is therefore impossible to set up freely a service area through the use of software.
Thus, the conventional systems cannot freely set up a mobile station service area for each service.